Heat Transfer Through Cylindrical Wall | Online Calculator

Heat Transfer Coefficients Calculators







Heat Transfer Through a Tube Wall

The heat flow, transfered through a solid cylindrical wall, separating two fluids with different temperatures, is calculated by the following formula in the simplest case:

q = K × (Tf1 - Tf2);

K - heat transfer coefficient;

Tf1 , Tf2 - are the temperatures of fluids between which the heat exchange takes place.

The heat transfer coefficient k depends on the physical properties of the heat carrier, the flow regime and the thermal conductivity of the solid wall. The heat transfer coefficient of a cylindrical wall, referred to the length of the pipe, can be expressed in terms of the convection film coefficients of the wall surfaces:

K = π / [(1 / αa*D1) + (1 / 2λ)*Ln(D2 / D1) + (1 / αb*D2)];

αa , αb - convection film coefficients of the inner and outer wall surfaces;

λ - wall heat transfer coefficient;

D1 - inner diameter;

D2 - outer diameter.

In this calculation, heat transfer through a tube of length L, with inner diameter D1, outer diameter D2, and with wall thermal conductivity λ is considered. The tube wall separates a fluid A with a temperature Tfa and a fluid B with a temperature Tfb. For the calculation, the convection film coefficients αa, αb should also be specified, which can be calculated in this Section.

As a result of calculations, the temperatures of the wall surfaces Twa, Twb, power P and heat flow Q, transmitted through the wall, and also heat transfer coefficient of the wall K, calculated relative to the pipe length, are determined.

Heat transfer throw tube wall
Heat transfer throw tube wall calculation

INITIAL DATA

D1 - Tube inner diameter;


D2 - Tube outer diameter;


L - Tube length;


λ - Thermal conductivity coefficient of the tube wall (see table below);


Tfa - Fluid temperature inside the tube;


αa - Convection film coefficient of the inner surface of the tube;


Tfb - Fluid temperature outside the tube;


αb - Convection film coefficient of the outer surface of the tube.

RESULTS DATA

К - Heat transfer coefficient of the tube wall;


Q - Heat flow transmitted through the wall;


Р- Power transmitted through the wall;


Тwa - Temperature of the inner surface of the tube;


Тwb - Temperature of the outer surface of the tube.

Inner diameter (D1)

Outer diameter (D2)

Tube length (L)

Thermal conductivity (λ)

Inside temperature (Т)

Film coefficient (αа)

Outside temperature (Тfb)

Film coefficient (αb)

Heat transfer (К)

Heat flow (Q)

Power (Р)

Temperature (Тwa)

Temperature (Тwb)

BASIC FORMULAS

Heat transfer coefficient:

K = π / [(1 / αa*D1) + (1 / 2λ)*Ln(D2 / D1) + (1 / αb*D2)];

Heat flow:

Q = K*(Т - Тfb);

Power:

P = Q*L;

Wall temperature Тwa:

Т = (αa*π*D1 - q) / (π*D1a);

Wall temperature Тwb:

Тwb = (αbfb*π*D2 + q) / (π*D2b).

INITIAL DATA

D1 - Tube inner diameter;


D2 - Tube outer diameter;


L - Tube length;


λ - Thermal conductivity coefficient of the tube wall (see table below);


Tfa - Fluid temperature inside the tube;


αa - Convection film coefficient of the inner surface of the tube;


Tfb - Fluid temperature outside the tube;


αb - Convection film coefficient of the outer surface of the tube.

RESULTS DATA

К - Heat transfer coefficient of the tube wall;


Q - Heat flow transmitted through the wall;


Р- Power transmitted through the wall;


Тwa - Temperature of the inner surface of the tube;


Тwb - Temperature of the outer surface of the tube.

THERMAL CONDUCTIVITY COEFFICIENTS

Material

Thermal conductivity

W/m*ºC

(W/inch*ºF)

Copper

399 (5.62)

Gold

317 (4.64)

Aluminium

237 (3.34)

Graphite

168 (2.37)

Brass

110 (1.55)

Iron

80 (1.12)

Carbon steel

43 (0.6)

Lead

35 (0.49)

Stainless steel

15.1 (0.21)

Rock

3.37 (0.047)

Concrete

0.84 (0.012)

Glass

0.81 (0.011)

Plastic

0.25 (0.0035)

Wood

0.15 (0.0021)

Rock wool

0.045 (0.00063)

Cork

0.039 (0.00055)

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